Y. J. Kim, R. S. Varma / Tetrahedron Letters 46 (2005) 7447–7449
7449
placed in a glass test tube and mixed on a vortex mixer.
The mixture was subjected to the MW irradiation at
3. (a) Wenkert, E.; Goodwin, T. E. Synth. Commun. 1977, 7,
09; (b) Tsunoda, T.; Suzuki, M.; Noyori, R. Tetrahedron
4
Lett. 1980, 21, 1357; (c) Nagumo, S.; Matsukuma, A.;
Suemune, H.; Sakai, K. Tetrahedron Lett. 1993, 49, 10501;
6
00 W (two times for 15 s irradiation) in Panasonic
household MW oven until a crude mixture of the liquid
and a small quantity of unreacted GaCl3 remained,
which was filtered using a syringe filter to afford color-
less single phased liquid. This product was fully charac-
terized by NMR spectroscopy. (Yield: 94%) Anal. Calcd
for C H Cl GaN : C, 27.39; H, 4.31; N, 7.99. Found:
(
1
d) Yang, H.; Li, B.; Cui, Y. Synth. Commun. 1998, 28,
233; (e) Cameron, A. F. B.; Hunt, J. S.; Oughton, J. F.;
Wilkinson, P. A.; Wilson, B. M. J. Chem. Soc. 1953,
864.
3
4
. (a) Ji, S.-J.; Wu, L. J. Mol. Catal. A: Chem. 2003, 202, 41;
(b) Kawabata, T.; Mizugaki, T.; Ebitani, K.; Kaneda, K.
Tetrahedron Lett. 2001, 42, 8329; (c) De, S. K.; Gibbs, R.
A. Tetrahedron Lett. 2004, 45, 8141; (d) Qi, J.-Y.; Ji, J.-X.;
Yueng, C.-H.; Kwong, H.-L.; Chan, A. S. C. Tetrahedron
Lett. 2004, 45, 7719; (e) Velusamy, S.; Punniyamurthy, T.
Tetrahedron Lett. 2004, 45, 4917; (f) Ranu, B. C.; Jana, R.;
Samanta, S. Adv. Synth. Catal. 2004, 346, 446.
8
15
4
2
1
C, 27.46; H, 4.34; N, 8.02. H NMR (300 MHz,
DMSO-d , 25 ꢁC): d 9.12 (s, 1H, imidazolium ring);
6
7
.76 (s, 1H, imidazolium ring); 7.70 (s, 1H, imidazolium
ring); 4.16 (t, J = 7.1, H, –NCH R); 3.85 (s, 3H,
2
–
0
NCH ); 1.77 (m, 2H, –CH –); 1.25 (m, 2H, –CH –);
.91 (t, J = 7.0, 3H, –CH3). C{ H} NMR (75 MHz,
3 2 2
1
3
1
5
6
. Shimizu, K.-I.; Hayashi, E.; Hatamachi, T.; Kodama, T.;
Kitayama, Y. Tetrahedron Lett. 2004, 45, 5135.
DMSO-d , 25 ꢁC): d 136.5, 123.6, 122.2 (imidazolium
6
ring); 48.5 (–NCH R); 35.7 (–NCH ); 31.3 (–CH –);
2
3
2
. For leading reviews, see: (a) Welton, T. Chem. Rev. 1999,
99, 2071; (b) Wassercheid, P.; Keim, W. Angew. Chem.,
Int. Ed. 2000, 39, 3772; (c) Dupont, J.; de Souza, R. F.;
Suarez, P. A. Z. Chem. Rev. 2002, 102, 3667; (d) Olivier-
Bourbigou, H.; Magna, L. J. Mol. Catal. A 2002, 182–
1
8.7 (–CH –); 13.2 (–CH ).
2
3
3
. Acetalization—general procedure
1
83, 419; (e) Sheldon, R. Chem. Commun. 2001, 2399; (f)
Zhao, D.; Wu, M.; Kou, Y.; Min, E. Catal. Today 2002,
4, 157.
In a typical procedure, methanolic solution (1.0 mL) of
benzaldehyde (5.66 mmol) was placed in a round-
bottomed glass flask (25 mL) and [bmim][GaCl4]
7
7
. For use as solvents: (a) Rogers, R. D.; Seddon, K. R. Ionic
Liquids as Green Solvents: Progress and Prospects; ACS
Symposium Series 856; American Chemical Society:
Washington, DC, 2003; (b) Rogers, R. D.; Seddon, K.
R. Science 2003, 302, 792; (c) Kim, D. W.; Song, C. E.;
Chi, D. Y. J. Am. Chem. Soc. 2002, 124, 10278; (d) Grasa,
G. A.; Viciu, M. S.; Huang, J.; Zhang, C.; Trudell, M. L.;
Nolan, S. P. Organometallics 2002, 21, 2866; (e) Bates, E.
D.; Mayton, R. D.; Ntai, I.; Davis, J. D., Jr. J. Am. Chem.
Soc. 2002, 124, 926; (f) Adams, C. J.; Earle, M. J.;
Seddon, K. R. Chem. Commun. 1999, 1043; (g) Lee, H.;
Kim, D. B.; Kim, S.-H.; Kim, H. S.; Kim, S. J.; Choi, D.
K.; Kang, Y. S.; Won, J. Angew. Chem., Int. Ed. 2004, 43,
(
0.28 mmol) was added. The reaction mixture was stir-
red at room temperature for 30 min. After completion
of the reaction (TLC monitoring), the product was
extracted with ether and filtered through the short silica
column to remove any impurities, followed by vacuum
drying to afford pure dimethylacetal (81% yield).
Acknowledgements
This research was performed while the author held a
National Research Council Research Associateship
Award at Clean Processes Branch, National Risk
Management Research Laboratory, US Environmental
Protection Agency.
3
053.
8
. For use as catalyst: (a) Kim, H. S.; Kim, Y. J.; Lee, H.;
Park, K. Y.; Lee, C.; Chin, C. S. Angew. Chem., Int. Ed.
2
002, 41, 4300; (b) Kim, H. S.; Kim, Y. J.; Bae, J. Y.; Kim,
S. J.; Lah, M. S.; Chin, C. S. Organometallics 2003, 22,
498; (c) Brown, R. J. C.; Dyson, P. J.; Ellis, D. J.;
2
Welton, T. Chem. Commun. 2001, 1862; (d) Kim, H. S.;
Kim, J. J.; Kim, H.; Jang, H. G. J. Catal. 2003, 220, 44; (e)
da Silveira Neto, B. A.; Ebeling, G.; Goncalves, R. S.;
Gozzo, F.; Eberlin, M. N.; Dupont, J. Synthesis 2004,
1155; (f) Li, D.; Shi, F.; Peng, J.; Guo, S.; Deng, Y. J. Org.
Chem. 2004, 69, 3582.
References and notes
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